Monday, 5 February 2007

The Householder Gresswell Grange

Dear Householder

Gresswell Grange Lakes Environmental Works

As co-managers of the Gresswell Grange lakes, Darebin City Council and La Trobe University are responsible for the care and maintenance of the two (primary and secondary) stormwater treatment wetlands located on the corner of Grange Boulevard and Main Drive. This is in accordance with an ongoing management agreement between Darebin City Council and La Trobe University.

A recent outbreak of an introduced species of fish, Gambusia sp., in the Gresswell Grange Lakes, and the consequent threat to aquatic fauna and wetland ecosystems further downstream in the Melbourne Wildlife Sanctuary, has prompted the need to carry out new environmental works on the lakes affected.

The outbreak is most likely to have resulted by people unknowingly translocating Gambusia from other contaminated waterways.

The Gambusia is a declared Noxious fish species in Victoria and causes irreparable damage to wetland ecosystems. In order to eradicate the fish from these wetlands it is necessary to drain the wetlands and treat them with lime. This raises the pH levels and rids the ponds of the Noxious species. This process is safe and will have the added benefit of reducing suspended clay and making the pond water clearer. Any native fish collected during the draining will be moved to safe holding ponds at La Trobe University and returned for re-stocking after the works have been completed.

The environmental works program will be conducted by specialist staff and will commence in early February 2007 and be completed within 2 weeks. The works will involve:

1.    Draining the primary wetland

2.   Applying liquid lime to the base of the wetland

3.   Follow-up investigation to determine the need for further work

Any enquires about the environmental works should be directed to the Melbourne Wildlife Sanctuary, General Enquiries on 9479 1206.

Yours faithfully






George Paras                      Adam Shalekoff

Head Ranger                                  Co-ordinator

Melbourne Wildlife Sanctuary                                     Bushland Management

La Trobe University                                                    Darebin City Council

I     A La Trobe University

Wild I If©        I              conservation and

!     education centre

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